Various medical procedures require that one or more fluids be injected into the patient. Medical imaging procedures oftentimes involve the injection of contrast media into the patient, possibly along with saline or other fluids. Other medical procedures involve injecting one or more fluids into a patient for therapeutic purposes.
Consider the case where both contrast media and saline are to be injected into a patient in accordance with a certain injection protocol. This injection protocol may entail injecting a certain volume of contrast media at a certain flow rate into the patient, followed by injecting a certain volume of saline at a certain flow rate into the patient, followed by injecting a certain volume of contrast media at a certain flow rate into the patient. In the case where a power injector is being used to execute an injection protocol, it is common to monitor a pressure associated with both a contrast media injection and a subsequent saline injection. It is also common for a pressure threshold to be input to the power injector and to take one or more actions if this pressure threshold is reached or exceeded during both a contrast media injection and a saline injection phase of an injection protocol.
Fluid being injected into a patient may be unintentionally directed into patient tissue versus a vein. This is generally referred to as extravasation, and may be the result of a technologist missing the patient's vein entirely when inserting a catheter, by the technologist piercing through the vein when inserting the catheter, or by the vein rupturing during a fluid injection. A patency test or check may be undertaken prior to initiating an injection protocol. This patency check may entail manually injecting saline into the patient through the flowpath that is to be used for the actual injection procedure. If there is a blockage in the flowpath or if the flowpath terminates in patient tissue versus within the patient's vein, the technologist should feel “back-pressure” when pushing on the syringe plunger. The technologist may also touch the patient's skin in proximity to the injection site during the patency check to determine if fluid is entering the patient's vein—there may be a bulging of the patient's skin at the injection site if fluid is being directed into patient tissue versus the patient's vein.
Power injectors may be used to execute an injection protocol. A power injector generally includes what is commonly referred to as a powerhead. One or more syringes may be mounted to the powerhead in various manners (e.g., detachably; rear-loading; front-loading). Each syringe typically includes what may be characterized as a syringe plunger, piston, or the like. Each such syringe plunger is appropriately interconnected with an appropriate syringe driver that is incorporated into the powerhead, such that operation of the syringe driver axially advances the associated syringe plunger. One typical syringe driver is in the form of a ram that is mounted on a threaded lead or drive screw. Rotation of the drive screw in one rotational direction advances the associated ram in one axial direction, while rotation of the drive screw in the opposite rotational direction advances the associated ram in the opposite axial direction.
At least certain power injectors include a patency check or test feature that is software-based. A small quantity of saline (e.g., about 10 milliliters) may be injected at the maximum flow rate that is anticipated to be used for the actual injection protocol. This patency check injection is done prior to executing the injection protocol. The back-pressure that develops during the patency check injection may be displayed. However, this pressure-monitoring functionality is not integrated with the patency check functionality. That is, pressure information is not provided to the logic that controls the patency check injection.